Multi Riser FCC Process for High CCR Resid Conversion
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Solution Overview
Problem
Current Fluid Catalytic Cracking (FCC) processes face challenges in efficiently processing feedstocks with high boiling temperatures and high concentrations of Conradson Carbon Residue (CCR) and metal impurities, leading to catalyst deactivation and reduced product yields, as existing methods are costly and limited in handling high CCR and metal levels.
Innovation Solution
A multiriser FCC apparatus using adsorbent and catalyst regenerators, with a common stripper cum separator vessel, where feed impurities are removed in a first riser reactor using an adsorbent and further cracking occurs in a second riser reactor with a catalyst, enhancing separation efficiency through differences in particle size and density, and separate regeneration of adsorbent and catalyst, thereby extending catalyst life and improving product yields.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high CCR and metal-containing residual oils are processed in conventional FCC, then conversion to lighter products is attempted, but catalyst deactivation occurs rapidly reducing catalyst longevity and product yields
Solution Approach 1:
The process divides the cracking operation into two separate riser reactors: a first riser for initial cracking of residual oil and a second riser for further cracking of liquid products. This segmentation allows the catalyst to be protected from direct contact with high CCR feedstock while still achieving conversion through controlled sequential processing.
Solution Approach 2:
The first riser reactor performs preliminary cracking of the high CCR residual oil before the cracked products enter the second riser reactor with fresh catalyst. This preliminary action removes the most harmful components (coke precursors, metals, high CCR materials) before they can deactivate the main catalyst inventory.
2Quantity of substance
If high boiling temperature feedstocks are processed in conventional FCC, then heavier residues are converted, but catalyst deactivation increases due to metal impurities and high CCR
Solution Approach 1:
The process extracts and removes harmful components (metals, high CCR materials, coke precursors) in the first riser reactor before the cleaned cracked products contact the main catalyst in the second riser reactor. This extraction protects the catalyst from poisoning while still enabling processing of heavy residues.
Solution Approach 2:
The first riser reactor acts as an intermediary unit that processes the toxic high CCR feedstock and transforms it into less harmful liquid products before these products enter the second riser reactor. This intermediary step mediates between the harmful feedstock and the sensitive catalyst.
3Device complexity
If conventional single riser FCC is used for resid cracking, then process simplicity is maintained, but catalyst activity dilution occurs reducing conversion efficiency
Solution Approach 1:
The process segments the cracking operation into two distinct riser reactors with different functions: the first riser handles high CCR feedstock cracking while the second riser handles liquid product cracking with fresh catalyst. This segmentation prevents catalyst activity dilution by separating the contaminated first-riser catalyst from the fresh second-riser catalyst.
Solution Approach 2:
Each riser reactor is designed with local quality optimized for its specific function: the first riser is optimized for handling high CCR feedstock with appropriate catalyst-to-oil ratio, while the second riser is optimized for maximizing conversion of liquid products with fresh, high-activity catalyst. This local optimization maintains high conversion efficiency throughout the system.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach effectively converts high CCR and metal-containing residual oils into lighter products, extending catalyst longevity and increasing yields of high-value products like propylene and gasoline, while maintaining heat balance and reducing catalyst deactivation, thus offering a more economical and efficient processing method.
Implementation Method 1
feed impurities are removed in a first riser reactor using an adsorbent
Implementation Method 2
further cracking occurs in a second riser reactor with a catalyst
Implementation Method 3
adsorbent and catalyst regenerators, with a common stripper cum separator vessel
Data Source
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AI summary
This invention provides a fluidized catalytic cracking apparatus and process for converting a hydrocarbon feedstock containing higher concentrations of Conradson Carbon Residue (CCR), metal impurities, etc into lighter products by employing two riser reactors in which the feed impurities are removed using an adsorbent in a first riser reactor and cracking a portion of first riser reactor liquid product in a second riser reactor to lighter products using the active catalyst thus eliminating the catalyst deactivation due to metal, impurities and FCC catalyst activity dilution effect to achieve a better conversion and higher catalyst longevity.